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The experiment is studied on thermal distribution in the thermal energy storage system with non-phase change materials (NPCM): NaNO3, KNO3 and NaCl in the range of 25˚C-250˚C. The cylindrical storage system was made of stainless steel with 25.6 cm-diameter and 26.8 cm-height that was contained of these NPCM. There was one pipe for heat transfer fluid (HTF) with 1.27 cm-diameter that manipulates in the storage tank and submerges to NPCM. The inner pipe was connected to the 2.27 cm-diameter outer HTF tube. The tube was further connected to the thermal pump, heater and load. The pump circulates the synthetic oil (Thermia oil) within the pipe for heat transferring purposes (charging and discharging). An electric heater is used as the heat source. The limitation of the charging oil temperature is maintained at 250˚C with the flow rates in the range of 0.58 to 1.45 kg/s whereas the inlet temperature of the discharge oil is maintained at 25˚C. Thermal performances of TES (thermal energy storage) such as charging and discharging times, radial thermal distribution, energy storage capacity and energy efficiency have been evaluated. The experimental results show that the radial thermal distribution of NaCl for TR inside, TR middle and TR outside was optimum of temperature down to NaNO3 and KNO3 respectively. Comparison of NPCMs with oil, flow rates for NaCl were charging and discharging heat transfer than KNO3 and NaNO3. The thermal stored NaCl ranged from 5712-5912 J; KNO3 ranged from 7350-7939 J and NaNO3 ranged from 6623-6930 J respectively. The thermal energy stored for experimental results got with along the KNO3, NaNO3 and NaCl respectively. The thermal energy efficiency of NaCl, KNO3 and NaNO3 was in the range 66%-70%.

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A novel technique has been developed for PV array internal resistance measurement while keeping the plant in operation in contrary to flash test or basic equation (Eb) for which the modules need to be disconnected from the system. We present an equation developed for the array’s internal resistance measurement for PV technologies namely Amorphous Silicon (a-Si), Poly Crystalline Silicon (p-Si) and Hybrid Crystalline Silicon (HIT). Monthly Measured I-V characteristic curves of PV Array were converted to Standard Test Conditions following the IEC 60891 standard. Multiple regression analysis and linear regression technique were used to develop the equation for estimating the PV array internal resistance. The developed equations (Ed) will find the relationships of the 4 variables that are Series resistance (Rs), Shunt resistance (Rsh), maximum voltage (Vm) and maximum current (Im). The results revealed that the Ed can be applied to measure the PV array internal resistance value with low error margin than Eb. The series resistance calculated using Ed is higher than Eb about 1.11 %, 1.88 % and 0.87 % for a-Si, p-Si and HIT respectively. The shunt resistance calculated using Ed is higher than Eb about 0.07 %, 0.09 % and 0.09% for a-Si, p-Si and HIT respectively.

A combination of solar hot water system with the economizer for heating the water that circulates in the hot water storage tank is presented with the objective to reduce and analyze the cost of investment. The solar collector area will be affected to the investment cost of the solar hot water system. A combined system can be reduced the cost of solar collector by using the waste heat from the economizer to produce the hot water for reaching the requirement of the industry. In this paper the economizer installs in the boiler stack of the industry and produces hot water at 60 C of 5,400 liter per day and the solar hot water system produces the hot water at the same temperature of 6,100 liter per day. The analysis is proposed by determining the solar collector plate area from the data and calculation. Investment cost of the system is 151,000 baht for the solar hot water system of 110,000 baht and the economizer of 410,000 baht for producing the total hot water of 115,000 liter per day.